How do I avoid quads appearing as triangles when twisting a mesh?
Method 1
You need to switch to smooth shaded mode with &quot;auto smooth&quot; enabled (auto smooth makes a hard normal on every edge that is greater than the set angle).

Method 2
Another method would be to manually mark the edges as sharp, then use an edge split modifier. First select all the &quot;sharp&quot; edges in edit mode, then hit Ctrl+E --&gt; &quot;Mark Sharp&quot;. (Make sure you already clicked Smooth in object mode)

Then add an edge split modifier that splits based on sharp edges.

Note: Hitting Smooth in object and edit mode do different things (you can smooth certain parts of the mesh in edit mode). For this solution, you will want to hit Smooth while in object mode.